MSI MAG B550 TOMAHAWK: no display and EZ Debug LEDs

Start with the display path

The motherboard's HDMI and DisplayPort sockets require a processor with compatible integrated graphics. Their presence does not make every AM4 CPU able to output video. If the build uses a discrete graphics card, connect the monitor to that card and select the matching monitor input.

Try a known-working cable before changing firmware. If the PC previously worked, record what changed: CPU, memory, graphics card, settings or simply the monitor connection.

Observe the LED that stays on

Watch the CPU, DRAM, VGA and BOOT indicators and record the one that remains lit. A brief transition between indicators differs from getting stuck.

• CPU or DRAM: check processor support, required BIOS, CPU power and memory installation.
• VGA: inspect the selected graphics path, card seating and its power connections.
• BOOT: investigate the boot drive and boot configuration. A graphics-driver reinstall is not a first response to a pre-Windows boot-device indicator.

Check compatibility before recovery

Use this exact board's CPU support list. An AM4 socket match is insufficient: MSI's specification explicitly excludes Ryzen 5 3400G and Ryzen 3 3200G. Other supported processors can depend on the installed BIOS release. Avoid firmware intended for another TOMAHAWK model.

Reduce the configuration methodically

Power off and disconnect mains before reseating components. Follow the manual's recommended single-module memory position and keep the CPU cooler installed. Retain a graphics card if the CPU cannot provide video. Reconnect optional devices one at a time after a minimal configuration starts.

If a CMOS reset becomes necessary, follow the model manual, record settings and prepare any encryption recovery information. Do not clear CMOS or interrupt power during a BIOS update.

Persistent failure with compatible parts is a reason to collect the LED state, CPU, BIOS and complete memory part number for support. The useful result of this checklist is a reproducible failure stage, not an unsupported verdict that a component must be replaced.